Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
|---|
| lassa fever virus: properties and characteristics. | 1979 | 111436 | |
| lassa virus antibodies in hospital personnel in western liberia. | the sera of 844 liberian hospital staff memebers were positive for lassa virus (lv) antibodies in a survey using the indirect fluorescent antibody technique (ifat). in two hospitals in lofa county near the sierra leone border, the prevalence, 15.4%, was significantly higher than the 8.4% in seven others. there were near differences between the prevalence among laboratory workers, 15.3%, and other workers, 7.7%, and between midwifery students, 21.2%, and midwives, 4.2%, suggesting their infection ... | 1979 | 382467 |
| isolated case of lassa fever in zaria, northern nigeria. | 1980 | 6107442 | |
| new emerging viral zoonoses. | new developments in the field of viral transmission from animal to man can be divided into four areas of study. first are the new viral zoonoses such as diseases caused by rotaviruses, lassa virus and the animal orthopox viruses which will be more prevalent after the cessation of mandatory vaccination against smallpox. secondly are the numerous ubiquitous viruses, such as adeno and herpesviruses, which in healthy animals lead only to clinically inapparent infections. a typical example of the thi ... | 1980 | 6254232 |
| monoclonal antibodies to lymphocytic choriomeningitis virus react with pathogenic arenaviruses. | certain arenaviruses have become widely recognized as important human pathogens, the most notable among these being lassa virus, the causative agent of lassa fever. two other members of the group, junin and machupo virus, are the aetiological agents of argentine and bolivian haemorrhagic fevers, respectively. all these agents share both morphological features and to varying degrees serological cross-reactivity with other non-pathogenic arenaviruses. despite the evident clinical importance of the ... | 1980 | 6160402 |
| preparation and use of erythrocyte-globulin conjugates to lassa virus in reversed passive hemagglutination and inhibition. | conditions were defined for functional covalent coupling of anti-lassa virus globulins to glutaraldehyde-fixed chicken erythrocytes. tolylene-2,4-diisocyanate in a reaction mixture containing not more than 0.01 m nacl produced uniformly good conjugates which were used in reversed passive hemagglutination (rph) and reversed passive hemagglutination inhibition (rphi) tests to detect lassa virus antigens in infected cell cultures and specific antigens in vero cell cultures. identical results were o ... | 1980 | 7000810 |
| lassa virus infection of rhesus monkeys: pathogenesis and treatment with ribavirin. | rhesus monkeys were experimentally infected with lassa virus to establish their suitability as a nonhuman primate model for the human disease and to test the protective efficacy of ribavirin, an antiviral drug. six of 10 untreated control monkeys died after subcutaneous inoculation of 10(6.1) plaque-forming units of lassa virus (strain josiah). infectivity titrations of tissue homogenates from the six dead monkeys indicated significant replication in all tissues tested except the central nervous ... | 1980 | 6768812 |
| effect of storage temperature on the stability of lassa virus complement-fixing antigen. | inactivated lassa virus complement-fixing antigen is normally prepared as a wet frozen antigen, and shipped in dry ice from the center for disease control, atlanta, georgia, usa, to other laboratories not equipped for handling live lassa virus. however, with this antigen there is a considerable loss of potency during shipping. in the search for a more stable antigen, inactivated lassa antigen was lyophilized and subjected to different storage temperatures. lyophilization did not significantly af ... | 1980 | 6772319 |
| clinical observations in 42 patients with lassa fever. | under continuous observation of several months, 42 patients from the eastern province of sierra leone, liberia (lofa county), and neighbouring guinea were identified as lassa fever cases by indirect immunofluorescent antibody technique, indicating that the disease is endemic in these areas. the clinical course varied from mild disease to severe illness with haemorrhagic disorders. the fatality rate was 14%. the occurrence of only two possible secondary cases suggests that person-to-person spread ... | 1980 | 7233535 |
| exotic infectious diseases: lassa fever]. | 1980 | 7384424 | |
| [accumulation of certain arenaviruses in transplantable vero and bhk-21 cells]. | production of lassa and machupo viruses in vero and bhk-21 cells was studied in relation to various conditions of the infected cell cultivation and as a function of different multiplicities of infection. the highest titers (expressed in pfu/ml) were obtained when the cells were grown in roller bottles with daily changes of the medium. the maximum titer in lassa virus-infected cells was over 10(6), in machupo virus-infected cells over 10(7). the effect of the autointerfering factor on the growth ... | 1981 | 7269524 |
| [effect of certain physico-chemical factors on arenaviruses]. | 1981 | 7269531 | |
| [effect of ribovirin (virazole) on arenavirus reproduction in cell cultures]. | 1981 | 7269532 | |
| [acute and chronic lassa virus infection of vero cells]. | acute and persistent infections of vero cells with a cloned lassa virus were studied. after acute infection at a multiplicity of 2 pfu/cell the latent period was 12-16 hrs and the maximum yield of virus particles in the growth medium was obtained 28-32 hours postinfection. a persistently infected cell line was established by inoculating vero cells with the cloned lassa virus followed by subcultivation of the infected cells. the infected cells underwent 36 passages. lassa virus production by the ... | 1981 | 7303630 |
| a comparison of indirect immunofluorescence and electron microscopy for the diagnosis of some haemorrhagic viruses in cell cultures. | yellow fever, dengue (types 1, 2 and 4), chikungunya, rift valley fever, ebola, marburg, and lassa viruses were inoculated into susceptible cell cultures and daily investigated by indirect immunofluorescence (ifa) and electron microscopy (em) with a view to achieve an early detection-identification of these agents. compared to the other cell lines tested (vero, bhk-21 and aedes albopictus), cv-1 cells were found to be more sensitive. viral antigens were detected by ifa from a few hours post inoc ... | 1981 | 7024293 |
| preparation of polyvalent viral immunofluorescent intracellular antigens and use in human serosurveys. | a method is described for preparation of polyvalent antigens for use in rapid screening for immunofluorescent antibodies to lassa, marburg, and ebola viruses. the technique uses mixtures of specifically infected vero cells placed on teflon-templated microscopy slides. it was found to be as sensitive as the use of monovalent antigens for detection and quantitation of antibodies to these highly hazardous human pathogens. | 1981 | 7031084 |
| recovery of a lassa-related arenavirus in zimbabwe. | immunofluorescent antibodies to "mozambique" virus, a close relative of lassa virus, were found in 11 of 55 mastomys natalensis and 1 of 13 aethomys chrysophilus rodents captured near que que and chiredzi, zimbabwe. six strains of mozambique virus, identified by use of specific monoclonal antibodies to the agent, were recovered from visceral tissues of m. natalensis rodents. all mastomys having virus or antibodies to this agent were of the chromosomal form 2n = 32 (m. natalensis). these data ext ... | 1981 | 7034562 |
| pathogenesis of a pichinde virus strain adapted to produce lethal infections in guinea pigs. | a model for studying the pathogenesis of virulent arenavirus infection was developed by adapting pichinde virus to produce lethal infections of inbred guinea pigs. this adapted pichinde virus retained low virulence for primates, thus potentially reducing the biohazard to investigators. whereas all inbred (strain 13) guinea pigs were infected and killed by 3 plaque-forming units or more of adapted pichinde virus injected subcutaneously, outbred (hartley strain) guinea pigs were relatively resista ... | 1981 | 6265367 |
| [further comment on lassa fever]. | 1981 | 6914002 | |
| experimental infection of rhesus monkeys with lassa virus and a closely related arenavirus, mozambique virus. | as a model for the pathogenesis of lassa fever in humans, nine rhesus monkeys were inoculated with lassa virus. three monkeys had had a previous asymptomatic experimental infection with mozambique virus, a closely related arenavirus; these monkeys were protected from illness and viremia and manifested only mild pathologic lesions. the other animals developed severe disease and viremia. at necropsy, hepatocellular necrosis, interstitial pneumonia, a unique pulmonary arteritis, adrenal gland necro ... | 1982 | 6286795 |
| use of betapropionolactone inactivated ebola, marburg and lassa intracellular antigens in immunofluorescent antibody assay. | 1982 | 7049096 | |
| the binding of staphylococcal protein a by the sera of different animal species. | the capacity of purified immunoglobulin or serum to bind (125i)-labeled staphylococcal protein a (spa) was measured by means of an immunofiltration assay that facilitated the examination of large numbers of sera and required only a minute quantity of each. sera from 80 species, including humans, laboratory animals, domestic animals, and a variety of african mammals were examined. a wide interspecies variation in the spa-binding capacity of serum immunoglobulins was confirmed. only small variatio ... | 1982 | 7061862 |
| [factors affecting plaque formation by lassa virus in vero cells]. | the method of porterfield and allison was adapted for titration of the infectious activity of lassa virus by the plaque formation in vero cells. the virus was cloned, and the effect of the time of adsorption, ph, temperature, as well as polycations (dead-dextran, protamine sulphate) dimethylsuphoxide (dmso), and trypsin added during adsorption or into the agar overlay on the effectiveness of plaque production by lassa virus (virus titres, plaque size) were studied. the optimal adsorption time wa ... | 1982 | 7072230 |
| pathologic and virologic study of fatal lassa fever in man. | postmortem examination of 21 virologically documented cases of lassa fever, including 6 complete autopsies, was performed as part of a field study of community-acquired lassa fever in sierra leone. the most consistently observed lesions were hepatocellular, adrenal, and splenic necrosis and adrenal cytoplasmic inclusions. neither these lesions, nor other milder and less constantly observed lesions such as myocarditis, renal tubular injury, and interstitial pneumonia, appeared severe enough to ex ... | 1982 | 7081389 |
| pathology of lassa virus infection in the rhesus monkey. | the clinical signs and gross and microscopic lesions of lassa virus infection in the rhesus monkey are described. of 17 monkeys infected with lassa virus, nine died or were killed when moribund. the clinical signs were lethargy, aphagia, constipation, fever, conjunctivitis, and skin rash. pulmonary congestion, pleural effusion, pericardial edema, hydropericardium, and a few visceral hemorrhages were present grossly. major microscopic lesions were necrotizing hepatitis and interstitial pneumonia. ... | 1982 | 7125056 |
| inactivation of lassa, marburg, and ebola viruses by gamma irradiation. | because of the cumbersome conditions experienced in a maximum containment laboratory, methods for inactivating highly pathogenic viruses were investigated. the infectivity of lassa, marburg, and ebola viruses was inactivated without altering the immunological activity after radiation with co60 gamma rays. at 4 degrees c, lassa virus was the most difficult to inactivate with a rate of 5.3 x 10(-6) log 50% tissue culture infective dose per rad of co60 radiation, as compared with 6.8 x 10(-6) log 5 ... | 1982 | 7153317 |
| haemorrhagic fever in gabon. i. incidence of lassa, ebola and marburg viruses in haut-ogooué. | a serological enquiry aimed at determining the incidence of infection with lassa, ebola and marburg viruses was conducted on the human population of the region of haut-ogooué (gabon) and on primates. the results, obtained by the indirect immunofluorescence technique, showed that more than 6% of the human population had had contact with ebola virus but no antibodies against marburg or lassa viruses were found. most sera reacted to an ebola antigen from a zairian strain, but showed little or no re ... | 1982 | 7164137 |
| glycoprotein detection in nitrocellulose transfers of electrophoretically separated protein mixtures using concanavalin a and peroxidase: application to arenavirus and flavivirus proteins. | 1982 | 7165111 | |
| lassa fever in children. | 1982 | 7185979 | |
| [a patient with lassa fever from the upper volta, diagnosed in the netherlands]. | 1982 | 7200196 | |
| pathogenesis of lassa virus infection in guinea pigs. | a rodent model for human lassa fever was developed which uses inbred (strain 13) and outbred (hartley) guinea pigs. strain 13 guinea pigs were uniformly susceptible to lethal infection by 2 or more pfu of lassa virus strain josiah. in contrast, no more than 30% of the hartley guinea pigs died regardless of the virus dose. in lethally infected strain 13 guinea pigs, peak titers of virus (10(7) to 10(8) pfu) occurred in the spleen and lymph nodes at 8 to 9 days, in the salivary glands at 11 days, ... | 1982 | 6749685 |
| viral haemorrhagic fever antibodies in zimbabwe schoolchildren. | 1982 | 6761909 | |
| physical and chemical methods of inactivating lassa virus. | 1982 | 6122855 | |
| inactivating lassa and marburg/ebola viruses. | 1982 | 6123862 | |
| marburg, ebola and rift valley fever virus antibodies in east african primates. | sera from 464 primates held at four institutes in kenya were tested by indirect immunofluorescence for the presence of antibodies against marburg, ebola, congo haemorrhagic fever, rift valley fever and lassa viruses. four of 136 vervet monkeys were positive for marburg virus antibodies and three of 184 baboons had antibodies against ebola virus. one baboon was positive for marburg virus antibodies. two vervet monkeys, three baboons and one grivet monkey (of 56 tested) had antibodies against rift ... | 1982 | 6810518 |
| a case of lassa fever: clinical and virological findings. | five days after arriving in london from jos a young nigerian women developed a severe and prolonged illness that proved to be lassa fever. virus was not detected in urine during the first three weeks but then appeared and reached a peak during the sixth week, with continuing excretion for 67 days after the onset of illness. laboratory investigations showed evidence of extensive tissue damage and disturbance of clotting, but there was no serious bleeding and she eventually made a complete recover ... | 1982 | 6812716 |
| case-control study of mastomys natalensis and humans in lassa virus-infected households in sierra leone. | lassa virus infection and antibodies were studied in households where lassa fever cases occurred, and compared to those in nearest neighbor houses and "far" houses located across the village from case houses. seventy-nine percent of all rodents caught in the houses were mastomys, the natural reservoir of lassa virus. rodent infection was not randomly distributed, but rather focal. thirty-nine percent of the mastomys in case houses were viremic, compared to 3.7% in control houses. human antibody ... | 1983 | 6881432 |
| modifications to indirect immunofluorescence tests on lassa, marburg, and ebola material. | 1983 | 6131336 | |
| reproduction of lassa virus in different cell cultures. | sierra leone strain of lassa virus was growing to high titres of 10(5)-10(6) plaque forming units (pfu) per ml in vero, l and swine kidney cell lines as well as in diploid human cells and primary human embryo kidney cells. as many as 80% of the cells became infected as demonstrated by the immunofluorescence (if) technique. in bhk-21, cv-1, hela, fl, hep-2 and dog kidney cell lines, the virus reproduced to lower titres (10(4)-10(5) pfu per ml), whereas in primary chick embryo fibroblasts it did n ... | 1983 | 6138991 |
| protection of lassa virus-infected guinea pigs with lassa-immune plasma of guinea pig, primate, and human origin. | lassa virus-immune plasma has been used to treat human lassa fever patients; however, criteria for plasma selection were based arbitrarily on available serologic tools and protective efficacy was never directly assessed. to test the validity of plasma therapy for lassa virus infections in an animal model, and to develop biologically relevant criteria for selection of protective immune plasma, inbred, strain 13 guinea pigs were infected with a lethal dose of lassa virus and treated with various l ... | 1983 | 6619814 |
| viral haemorrhagic fever surveillance in kenya, 1980-1981. | following two cases of marburg virus disease in kenya in 1980, viral haemorrhagic fever surveillance was undertaken in western kenya. over a 21-month period investigations, including virus isolation attempts, patient and contact serology, visits to areas where suspected cases occurred, interviewing family members and neighbours of suspected cases and following up any additional illnesses in these areas, were carried out. during the study two cases were found that were likely to have been ebola h ... | 1983 | 6684336 |
| structural and cell-associated proteins of lassa virus. | lassa virus was purified from culture fluids of infected cv-1 monkey kidney cells and its structural proteins analysed by polyacrylamide gel electrophoresis. stained gels showed a typical arenavirus profile, with a prominent protein of molecular weight 60000, corresponding to the nucleocapsid protein n, and two faint broad bands with molecular weights of 45000 and 38000, the envelope glycoproteins g1 and g2. g1 and g2 were shown to be glycosylated by their ability to bind concanavalin a to nitro ... | 1983 | 6405010 |
| antibodies against haemorrhagic fever viruses in kenya populations. | human sera from lodwar (77 sera), nzoia (841 sera), masinga (251 sera), laisamis (174 sera) and the malindi/kilifi area (556 sera) in kenya were tested by indirect immunofluorescence for antibodies against marburg, ebola (zaire and sudan strains), congo haemorrhagic fever, rift valley fever and lassa viruses. antibodies against ebola virus, particularly the zaire strain, were detected in all regions and were, over-all, more abundant than antibodies against the other antigens. ebola and marburg a ... | 1983 | 6419422 |
| possible approaches to a vaccine against lassa fever. | 1984 | 6464128 | |
| physicochemical inactivation of lassa, ebola, and marburg viruses and effect on clinical laboratory analyses. | clinical specimens from patients infected with lassa, ebola, or marburg virus may present a serious biohazard to laboratory workers. we have examined the effects of heat, alteration of ph, and gamma radiation on these viruses in human blood and on the electrolytes, enzymes, and coagulation factors measured in laboratory tests that are important in the care of an infected patient. heating serum at 60 degrees c for 1 h reduced high titers of these viruses to noninfectious levels without altering t ... | 1984 | 6490832 |
| effect of environmental factors on aerosol-induced lassa virus infection. | previous studies suggested that the most frequent means of transmission of lassa virus was by either direct or indirect contact with infectious material. aerosol stability and respiratory infectivity of the josiah strain of lassa virus were assessed to determine the effect of environmental factors on aerosol-induced infection. the stability of the virus in aerosol, particularly at low relative humidity (30% rh), plus the ability of the virus to infect guinea pigs and monkeys via the respiratory ... | 1984 | 6512508 |
| ribonucleic acids of machupo and lassa viruses. | sucrose gradient velocity centrifugation, polyacrylamide gel electrophoresis and rna-rna hybridization were used to characterize lassa and machupo virion rnas as well as virus-specific rnas from cells infected with pichinde and machupo viruses. five rna species: 30-31s, 28s, 22-24s, 18s and 4-6s have been detected in lassa, machupo, and pichinde virion rnas. among them 28s, 18s and 4-6s rnas cosediment and comigrate with respectively cell rnas. rnase resistance analyses suggest the presence of e ... | 1984 | 6320777 |
| detection of lassa virus antigens and lassa virus-specific immunoglobulins g and m by enzyme-linked immunosorbent assay. | rapid diagnosis of lassa fever is desirable for the timely therapeutic intervention and implementation of strict quarantine procedures both in west africa field hospitals where the disease is endemic and at international crossroads. an enzyme-linked immunosorbent assay (elisa) to measure lassa virus antigens in viremic sera was developed in which experimentally infected monkeys were used as a model for the human disease. in this test, lassa virus antigens in test sera were captured in wells of m ... | 1984 | 6386846 |
| endemic lassa fever in liberia. ii. serological and virological findings in hospital patients. | patients admitted with fever to four liberian hospitals were tested for lassa fever (lf) by means of the indirect fluorescent antibody technique and by virus isolation. the incidence of lf and presumptive lf among consecutive febrile adult patients was 14% and 17% in two hospitals located in the interior; no cases of lf were found among 24 consecutive patients in a hospital near the coast. in the three inland hospitals the incidence of confirmed or presumptive lf among the patients in whom the d ... | 1984 | 6390808 |
| endemic lassa fever in liberia. v. distribution of lassa virus activity in liberia: hospital staff surveys. | serological testing of hospital personnel by the indirect fluorescent antibody (ifa) technique was used to indicate the distribution of lassa virus (lv) activity in liberia. determination of the places of origin of the staff members as well as the sites of the hospitals indicated that lv is active in throughout liberia. prevalences of ifa varied from 3.8% at the j. j. dossen hospital on the coast in the south-east to 22.3, 23.5 and 40.4% in lofa county hospitals inland in the north-west. rises i ... | 1984 | 6398529 |
| endemic lassa fever in liberia. vi. village serological surveys for evidence of lassa virus activity in lofa county, liberia. | six villages in lofa county, north-west liberia, and one near the coast were surveyed for the presence of indirect fluorescent antibodies (ifa) to lassa virus (lv). prevalences were similar among males and females, and among various age groups. the prevalence of ifa positive sera, 6.4%, in two roadside villages was significantly higher than in two matched villages "in the bush", 1.9%. it was also higher in gbanwei, a roadside village which did not maintain traditional sanitary measures, than in ... | 1984 | 6398530 |
| passive antibody therapy of lassa fever in cynomolgus monkeys: importance of neutralizing antibody and lassa virus strain. | lassa virus-infected cynomolgus monkeys were passively immunized with immune plasma of primate or human origin to gain insight into criteria for plasma selection and administration to human lassa fever patients. protective efficacy was correlated with neutralizing antibody concentrations, expressed as a log10 neutralization index (lni). convalescent lassa-immune monkey plasma was titrated for protective efficacy in monkeys by intravenous inoculation with dilutions of plasma on the day of subcuta ... | 1984 | 6715049 |
| enhanced treatment of lassa fever by immune plasma combined with ribavirin in cynomolgus monkeys. | lassa virus-infected cynomolgus monkeys were treated with lassa virus-immune monkey serum containing a high concentration of neutralizing antibody, the antiviral drug ribavirin, or a combination of ribavirin plus immune serum at various times after infection. when treatment was initiated early (day 0 or 4), either ribavirin (30 mg/kg of body weight per day) or immune serum alone protected monkeys. however, when the initial treatment was delayed until day 7, only four of eight ribavirin-treated a ... | 1984 | 6715898 |
| [inhibition of the accumulation of the lassa virus in vero cells by immune gamma globulin and complement]. | specific inhibition of lassa virus replication in vero cells was found to be better achieved with immune gamma globulin in combination with complement than with gamma globulin alone. according to the authors, the inhibitory effect of these preparations is due to the cyto-destructive action of antibodies and complement on the infected cells. | 1984 | 6208692 |
| indirect solid-phase immunosorbent assay for detection of arenavirus antigens and antibodies. | indirect enzyme-linked immunosorbent assay (elisa) and solid-phase radioimmunoassay (spria) using either anti-human or anti-mouse igg labelled with horseradish peroxidase and 125i, respectively, were developed for the detection of junin, machupo, tacaribe, amapari, tamiami, lassa and lcm arena-viruses. both methods allow high sensitivity detection of arena-virus antigens and antibodies. | 1984 | 6148001 |
| kinetic study of platelets and fibrinogen in lassa virus-infected monkeys and early pathologic events in mopeia virus-infected monkeys. | the rhesus monkey, an established model of lassa fever, was used to study hematologic and hemostatic aspects of lassa fever and whether mopeia (also known as mozambique) virus induces any cellular damage in this model. six days after subcutaneous injection of 10(3.48) plaque forming units (pfu) of lassa virus (josiah strain) one group of monkeys received an intravenous injection of 111in-labeled allogeneic platelets and another group received 125i-labeled alogeneic fibrinogen. lassa virus-infect ... | 1985 | 4037187 |
| lassa virus lethality for inbred mice. | 1985 | 4037900 | |
| [experimental evaluation of the pathogenicity of lassa virus variants]. | pathogenicity for guinea pigs and white mice of various lassa virus variants: native, having had 1 passage in vero cell culture and 4 passages in newborn white mouse brain; a virus having gone through 10 passages in vero cells and 8 mouse brain passages (variant no. 10); a small-plaque clone derived from variant no. 10 by the method of plaque-to-plaque cloning (variant no. 11k), was studied. both the native virus and variant no. 10 were found to be similarly pathogenic for susceptible laboratory ... | 1985 | 4060702 |
| [pathogenicity of the lassa virus for laboratory mice]. | pathogenicity for randombred and inbred mice of various age groups of the standard lassa virus and the virus enriched with defective interfering particles (dip) was studied. the standard lassa virus inoculated intracerebrally caused 100% death of c3h/sn mice aged up to 4 weeks and 60%-70% death of randombred white mice aged 3-4 weeks. balb/c mice were found to be nonsusceptible to the virus, and its lethality for c57bl/6 and akr mice varied within the range of 30%-60%. lassa virus enriched with ... | 1985 | 4072162 |
| effect of beta-propiolactone on routine biochemical investigations. | 1985 | 4079681 | |
| antibodies to lassa and lassa-like viruses in man and mammals in the central african republic. | 715 human sera from different locations in the central african republic were tested by indirect immunofluorescence against the three african arenaviruses, lassa, mobala and mopeia. four were positive for lassa, seven for mobala, and one for both lassa and mopeia. the epidemiology of african arenaviruses is discussed. | 1985 | 2986324 |
| molecular cloning of lassa virus rna: nucleotide sequence and expression of the nucleocapsid protein gene. | lassa virus rna isolated from purified virus particles was polyadenylated and reverse transcripts were cloned into the psti site of plasmid puc9. clones containing sequences of the smaller (s) segment of the lassa virus genome were identified by hybridization with purified s rna. they were characterized by their ability to hybridize with fragments of 3'-labeled lassa virus s rna and with each other, and by restriction mapping. the largest insert was 1830 bp long and began with the 3'-terminal 19 ... | 1985 | 3840620 |
| endemic lassa fever in liberia. iii. characterization of lassa virus isolates. | sixty-three virus isolates were obtained by inoculation of vero cells with sera from 50 hospital in-patients in liberia with acute febrile illnesses. 57 of the isolates were presumptively identified as lassa virus (lv) by direct fluorescent antibody (dfa) staining of inoculated vero cells. these, and six additional isolates obtained only by titration of supernatant fluids from inoculated vero cells, were definitively identified as lv in a neutralization test. two additional lv isolates were obta ... | 1985 | 3898483 |
| endemic lassa fever in liberia. iv. selection of optimally effective plasma for treatment by passive immunization. | the efficacy of passive immunization for treatment of lassa fever (lf) is believed to depend on the titre of the neutralizing antibody infused. for the purpose of identifying optimal donors of lv-immune plasma, a population of lf-convalescent patients in liberia was tested for prevalence of neutralizing antibody. minimally protective titres, expressed as a log10 neutralization index, (lni), were established in animal models as lni greater than 2. lni titres for 26 donors, tested eight or more mo ... | 1985 | 3898484 |
| [method for the simultaneous detection of immunofluorescing antibodies to the causative agents of different hemorrhagic fevers]. | 1985 | 3907144 | |
| early diagnosis of human lassa fever by elisa detection of antigen and antibody. | sequential serum samples, beginning on the day of hospital admission, from three patients with lassa fever were tested for the presence of lassa-virus antigens and antibodies by means of an enzyme-linked immunosorbent assay. lassa-virus antigens were detected in the first serum sample from each patient, thus providing an early definitive diagnosis. in contrast, seroconversion was not detectable by elisa or indirect fluorescent antibody techniques until 3 days or more after admission. the antigen ... | 1985 | 2857321 |
| identification of ippy as a lassa-fever-related virus. | 1985 | 2857974 | |
| sedimentation analysis of the rnas isolated from interfering particles of lassa and machupo viruses. | vero cells chronically infected with lassa virus as well as bhk-21 cells chronically infected with machupo virus produced particles interfering with the replication of homologous, but not heterogeneous viruses. rnas of standard virus particles contained 4 sedimentation classes of molecules: 28-31 s, 22-24s, 18 s and 4-6 s. the 28-31 s molecules were not present among the rnas of interfering particles of lassa and machupo viruses. | 1985 | 2869655 |
| no evidence for increased risk of lassa fever infection in hospital staff. | a prospective serological study was undertaken in hospital personnel who care for lassa fever (lf) patients in an endemic region of sierra leone, west africa. among personnel from three hospitals where barrier nursing is practised, antibody prevalence and seroconversion by age and sex were consistently equal to or lower than those of persons in nearby village populations. no group among hospital personnel evaluated by age, sex, contact, or occupational exposure was at higher risk than another. h ... | 1986 | 2877335 |
| lassa fever. effective therapy with ribavirin. | in a study of lassa fever in sierra leone, west africa, we identified two variables associated with a high risk of death, and we evaluated the efficacy of ribavirin and lassa virus-convalescent plasma for the treatment of lassa fever. a serum aspartate aminotransferase level greater than or equal to 150 iu per liter at the time of hospital admission was associated with a case-fatality rate of 55 percent (33 of 60). patients with the same risk factor who were treated for 10 days with intravenous ... | 1986 | 3940312 |
| lassa virus hepatitis: a study of fatal lassa fever in humans. | in order to explore the significance of a previous observation that the most important pathologic changes in fatal lassa fever are hepatic, we have studied postmortem liver biopsies from 19 patients with fatal lassa fever. we observed a vigorous macrophage response to cellular damage, but we found no evidence of lymphocyte infiltration in infected hepatic tissues. using semi-quantitative estimates of liver cell damage, we found a wide range in the severity and progression of lassa virus hepatiti ... | 1986 | 3953952 |
| use of monoclonal antibody for the detection of lassa virus antibody and antigen in patients with lassa fever. | 1986 | 3523183 | |
| expression of lassa virus nucleocapsid gene fragments in bacteria. | 1986 | 3523185 | |
| [indirect immunoenzyme method for the laboratory diagnosis of lassa and ebola hemorrhagic fevers]. | conditions for performing solid-phase indirect enzyme-immunoassay (speia) for the detection of lassa and ebola virus antigens and antibodies to them using horseradish peroxidase-labeled antispecific globulins were developed. the method is highly sensitive, specific, and reproducible. by this method, antigens of lassa and ebola viruses could be detected in tissue culture fluid of the infected cell cultures and in animal organ suspensions. detection of antibodies to lassa and ebola viruses in huma ... | 1986 | 3524001 |
| clinical, epidemiologic, and therapeutic aspects of lassa fever. | 1986 | 3724661 | |
| evolutionary biology of a lassa virus complex. | 1986 | 3724662 | |
| serological and biological evidence that lassa-complex arenaviruses are widely distributed in africa. | 1986 | 3724663 | |
| serology and virulence diversity among old-world arenaviruses, and the relevance to vaccine development. | 1986 | 3724664 | |
| some biochemical properties of lassa virus rna and polypeptides. | 1986 | 3724668 | |
| nucleotide sequence of the glycoprotein gene and intergenic region of the lassa virus s genome rna. | two overlapping cdna clones corresponding to the 5' region of the lassa virus s genome rna were isolated and their nucleotide sequences determined. similar to pichinde and lymphocytic choriomeningitis viruses (lcmv), lassa virus has an ambisense s rna. the precursor to the viral glycoproteins (gpc) is encoded in viral rna sequence originating at position 56 and terminating at position 1529 from the 5' terminus of the s rna. a short, noncoding, intergenic region capable of forming a hairpin struc ... | 1986 | 3750844 |
| hemorrhagic fever virus infections in an isolated rainforest area of central liberia. limitations of the indirect immunofluorescence slide test for antibody screening in africa. | serum samples from 119 healthy individuals and 106 epilepsy patients inhabiting grand bassa county, liberia, were tested for antibodies to hemorrhagic fever viruses (hfv) by indirect immunofluorescence. e6 vero cells infected with lassa fever virus (las), rift valley fever virus (rvf), congo hemorrhagic fever virus (con), marburg virus (mbg) and the ebola (ebo) virus strains mayinga (may) and boniface (bon) were used as antigen. to obtain reproducible and specific test results sera had to be abs ... | 1986 | 3092415 |
| lassa fever in children in sierra leone, west africa. | a systematic study of lassa fever in febrile children was undertaken over a four-year period, from august 1977 to august 1981, in the eastern province of sierra leone, west africa. 479 patients were studied; of these, 245 had adequate specimens to confirm or exclude the laboratory diagnosis of lassa fever. 51 cases of lassa fever were identified (21% of patients from whom diagnosis was possible). virus was isolated from 23 patients. all children had fever; cough and vomiting were present in over ... | 1986 | 3810792 |
| pediatric lassa fever: a review of 33 liberian cases. | thirty-three cases of pediatric lassa fever were identified at curran lutheran hospital and phebe hospital in liberia between january 1980 and march 1984. all 18 fetal cases died and the case-fatality rate for 15 childhood cases was 27%. we identified four clinical presentations according to age, including a case of congenital lassa fever, a condition not reported previously. two cases of lassa fever were found serologically during a one-month survey of all pediatric admissions at curran luthera ... | 1987 | 3826501 |
| [pathogenic machupo and lassa arenaviruses: the biochemical properties of virion rna and proteins]. | lassa virus purified in the isodensity sucrose concentration gradient had the following buoyant densities: 1.17 g/cm3 (sucrose), 1.19 g/cm3 (cesium chloride), 1.16 g/cm3 (urografin). similar parameters were obtained for machupo virus. virion rnas of these viruses contained 5 sedimentation classes of molecules: 30-31s, 28s, 22-24s, 18s, and 4-6s. experiments on hybridization of individual sedimentation classes of rna with an excess of poly(a)-containing rna from the infected cells as well as inhi ... | 1987 | 2825435 |
| [identification of the mrna of the nucleocapsid proteins of pathogenic arenaviruses]. | total rna from cells infected with machupo and lassa viruses as well as individual sedimentation classes of these rnas were translated in the cell-free protein-synthesizing system from rabbit reticulocytes. the translation products were precipitated either with anti-machupo immune gamma-globulin or monoclonal antibodies to nucleocapsid protein (np) of lassa virus. both total rna and rna fraction with the sedimentation coefficient 15-16s promoted the synthesis of protein which comigrated in gel w ... | 1987 | 2829439 |
| studies of the coagulation system in arenaviral hemorrhagic fever: experimental infection of strain 13 guinea pigs with pichinde virus. | significant coagulation abnormalities were associated with experimental infection of strain 13 guinea pigs with pichinde virus, an arenavirus related to the virulent human pathogens junin, machupo, and lassa viruses. infected animals developed decreased activity of multiple coagulation factors, decreased antithrombin iii levels, high levels of fibrin-fibrinogen degradation products, impaired platelet function, and thrombocytopenia. testing for the presence of a coagulation inhibitor revealed a p ... | 1987 | 3030150 |
| [clinico-epidemiologic and laboratory research on hemorrhagic fevers in guinea]. | in 1982-1983, were reported the cases of haemorrhagic fevers among populations living in the madina-ula district of guinea. clinico-epidemiological and serological studies (experimental studies) reveal into presumption of ebola and lassa fever viruses significance in the etiology of the disease outbreaks. antibodies to ebola virus were recognized in 19% from total number of sweating reconvalescent patients with the same clinical features, in order to 8% in healthy local populations. antibodies t ... | 1987 | 3440310 |
| expression of lassa virus nucleocapsid protein segments in bacteria: purification of high-level expression products and their application in antibody detection. | the lassa virus nucleocapsid protein gene and segments from it were expressed in escherichia coli under the control of the lac promoter in puc-based plasmids. expression of the near full-length protein [amino acid (aa) residues 12-570] fused to an n-terminal sequence of vector-derived 6 aa was not particularly efficient, and neither was that of a smaller n-terminal segment (aa 6-201) which was also fused at its c terminus to the remainder of the lacz gene product. by contrast, the c-terminal 370 ... | 1987 | 3315857 |
| lassa fever--new issues raised by field studies in west africa. | 1987 | 3805770 | |
| a prospective study of the epidemiology and ecology of lassa fever. | in studies of lassa fever in sierra leone, the prevalence of human antibody to lassa virus ranged from 8% to 52%. mastomys natalensis, the reservoir of lassa virus, constituted 50%-60% of the rodents captured in houses but only 10%-20% of those captured in surrounding agriculture and bush areas (chi 2 = 90.2, p less than 10(-6), df = 1), a finding suggesting that houses are the most-important location for transmission of lassa virus. viral infection of mastomys from houses ranged from 0% to 80%. ... | 1987 | 3805771 |
| clinical virology of lassa fever in hospitalized patients. | we measured levels of virus in sequential specimens from 137 patients with lassa fever. the probability of fatal disease increased significantly with the level of viremia measured either on admission or during the course of illness. the odds ratio of death in patients with viremia greater than 10 tcid50/ml was 3.7 (90% confidence interval, 1.9-7.2). the same ratio in patients with viremia greater than 10 tcid50/ml and with levels of aspartate aminotransferase greater than or equal to 150 iu/lite ... | 1987 | 3805773 |
| physiological and immunologic disturbances associated with shock in a primate model of lassa fever. | the degree of cell and organ damage in clinical and histological studies of patients dying of lassa fever has been insufficient to explain the catastrophic shock characteristic of the fatal illness. to explore this issue further, we conducted a study of the evolution of shock in three lassa virus-infected rhesus monkeys. by the sixth day after infection, a marked, progressive reduction of in vitro platelet aggregation occurred despite normal numbers of circulating platelets and a normal platelet ... | 1987 | 3543155 |
| standardization of a plaque assay for lassa virus. | the plaque reduction neutralization test (prnt) has been used routinely in serological studies with such arenaviruses as junin, machupo, and parana. however, difficulties have been encountered in using the prnt for lcm virus, while conflicting views have been expressed about the reliability and efficacy of the test with lassa virus. we have therefore investigated and evaluated the plaque assay for lassa virus. in addition, the suitability of the prnt for determining the potency of a serum and it ... | 1987 | 3585290 |
| [current serologic data on viral hemorrhagic fevers in the central african republic]. | during the years 1984-1985, 1,528 serum samples were taken through out the car. of these sera, 319 (20.8%) contained anti-filoviridae antibodies (ebola, marburg). this figure is higher than those found in cameroon, sudan, gabon and zaïre. three zones of the country are particularly exposed, the north-east where the population is in the contact with sudan ebola, the south-east where it is in contact with zaïre ebola, and the south-west where it is in contact with sudan ebola. the authors believe ... | 1987 | 3607998 |
| molecular structure and early events in the replication of tacaribe arenavirus s rna. | tacaribe arenavirus s rna was cloned and analysis of its nucleotide sequence revealed two open reading frames of significant size, one in the virus-sense strand, the other in the virus-complementary strand. the predicted amino acid sequences of the two reading frames were compared with the predicted primary structures of the nucleoprotein (n) and glycoprotein precursor (gpc) of lcm, pichinde and lassa viruses. the results indicated a high degree of homology between the proteins of similar proper ... | 1987 | 3617928 |
| vaccinia recombinant expressing lassa-virus internal nucleocapsid protein protects guineapigs against lassa fever. | the lister strain of vaccinia virus was used to construct a recombinant that expressed the nucleocapsid gene of lassa virus. guineapigs immunised with the recombinant virus were protected against challenge with lassa virus, whereas control animals showed the usual disease course, including pyrexia, anorexia, viraemia, and death. these data indicate not only that protective immunity to lassa fever can be evoked by an experimental vaccine, but also that this response can be mediated by an internal ... | 1987 | 2885642 |
| differentiation between two african arenaviruses (lassa and mozambique) by plaque assay. | the biological characteristics of lassa and mozambique viruses were compared by plaque assay. both viruses produced plaques under the same conditions, however, lassa virus plaques measured on average 2 mm in diameter being twice as large as the mozambique virus plaques. by plaque reduction tests, cross protection was demonstrated between both viruses showing that lassa and mozambique viruses are distinct but related. | 1987 | 2886023 |
| [characteristics of monoclonal antibodies against lassa virus]. | some properties of monoclonal antibodies to the lassa virus have been characterized. the competitive immunoenzyme analysis has revealed the presence of at least three antigens in the lassa virus nucleoprotein. | 1987 | 2441254 |
| fine mapping of a peptide sequence containing an antigenic site conserved among arenaviruses. | the lymphocytic choriomeningitis virus (lcmv) structural glycoproteins gp-1 (mr 44k) and gp-2 (mr 35k) are encoded on a single intracellular proteolytic cleavage precursor glycoprotein, gp-c (mr 76k). we have used a series of synthetic peptides derived from the deduced amino acid sequence of lcmv gp-c to define an antigenic site containing two topographically overlapping epitopes. three mouse monoclonal antibodies directed against two epitopes on gp-2 were assayed for binding in solution phase b ... | 1988 | 2452517 |
| identification of messenger rna for nucleocapsid protein of lassa virus in infected cells. | single-stranded rnas from lassa virus-infected cells were fractionated by affinity chromatography on an oligo(dt)-cellulose column as well as by sucrose gradient centrifugation. fractionated rnas were translated in rabbit reticulocyte lysates, and translation products were precipitated with monoclonal antibodies to the nucleocapsid protein of lassa virus. it has been shown that mrna for the nucleocapsid protein is 15-16s and the rna does not contain long if any poly(a) sequences. | 1988 | 2900821 |